Abstract

This paper investigates the CO 2 and N 2 O absorption behavior in the water-lean gamma amino propyl (GAP)-1/TEG solvent system using a wetted-wall contactor. Testing was performed on a blend of GAP-1 aminosilicone in triethylene glycol at varied water loadings in the solvent. Measurements were made with CO 2 and N 2 O at representative lean (0.04 mol CO 2/mol alkalinity), middle (0.13 mol CO 2 /mol alkalinity) and rich (0.46 mol CO 2 /mol alkalinity) solvent loadings at 0, 5, 10 and 15 wt% water loadings at 40, 60 and 80C° and N 2 O at (0.08-0.09 mol CO 2 /mol alkalinity) at 5 wt% water at 40, 60 and 80C°. CO 2 flux was found to be non-linear with respect to log mean pressure driving force (LMPD). Liquid-film mass transfer coefficients (k'g) were calculated by subtracting the gas film resistance (determined from a correlation from literature) from the overall mass transfer measurement. The resulting k'g values for CO 2 and N 2 O in GAP-1/TEG mixtures were found to be higher than that of 5M aqueous monoethanolamine under comparable driving force albeit at higher solvent viscosities. The k'g values for CO 2 were also found to decreasemore » with increasing solvent water content and increase with a decrease in temperature. These observations indicate that mass transfer of CO 2 in GAP-1/TEG is linked to the physical solubility of CO 2 , which is higher in organic solvents compared to water. This paper expands on the understanding of the unique mass transfer behavior and kinetics of CO 2 capture in water-lean solvents.« less

@article{osti_1355087,
title = {Measuring CO 2 and N 2 O Mass Transfer into GAP-1 CO 2 –Capture Solvents at Varied Water Loadings},
author = {Whyatt, Greg A. and Zwoster, Andy and Zheng, Feng and Perry, Robert J. and Wood, Benjamin R. and Spiry, Irina and Freeman, Charles J. and Heldebrant, David J.},
abstractNote = {This paper investigates the CO2 and N2 O absorption behavior in the water-lean gamma amino propyl (GAP)-1/TEG solvent system using a wetted-wall contactor. Testing was performed on a blend of GAP-1 aminosilicone in triethylene glycol at varied water loadings in the solvent. Measurements were made with CO2 and N2 O at representative lean (0.04 mol CO2/mol alkalinity), middle (0.13 mol CO2 /mol alkalinity) and rich (0.46 mol CO2 /mol alkalinity) solvent loadings at 0, 5, 10 and 15 wt% water loadings at 40, 60 and 80C° and N2 O at (0.08-0.09 mol CO2 /mol alkalinity) at 5 wt% water at 40, 60 and 80C°. CO2 flux was found to be non-linear with respect to log mean pressure driving force (LMPD). Liquid-film mass transfer coefficients (k'g) were calculated by subtracting the gas film resistance (determined from a correlation from literature) from the overall mass transfer measurement. The resulting k'g values for CO2 and N2 O in GAP-1/TEG mixtures were found to be higher than that of 5M aqueous monoethanolamine under comparable driving force albeit at higher solvent viscosities. The k'g values for CO2 were also found to decrease with increasing solvent water content and increase with a decrease in temperature. These observations indicate that mass transfer of CO2 in GAP-1/TEG is linked to the physical solubility of CO2 , which is higher in organic solvents compared to water. This paper expands on the understanding of the unique mass transfer behavior and kinetics of CO2 capture in water-lean solvents.},
doi = {10.1021/acs.iecr.7b00193},
journal = {Industrial and Engineering Chemistry Research},
number = 16,
volume = 56,
place = {United States},
year = {Wed Apr 12 00:00:00 EDT 2017},
month = {Wed Apr 12 00:00:00 EDT 2017}
}

The effect of hydration on the reactivity of O{sup {minus}}(H{sub 2}O){sub n} (n = 0-2) with the neutrals O{sub 2}, CO{sub 2}, CO, NO, SO{sub 2} CH{sub 4}, N{sub 2}O, and H{sub 2}O has been investigated as a function of temperature. Rate constants for the above reactions were measured at 251, 343, and 473 K ({sup {minus}}(H{sub 2}O){sub 2} reactions were studied at 251 and 343 K only) by using a variable-temperature fast-flow system that incorporates optionally either a selected ion source or a high-pressure ion source. Hydration of O{sup {minus}} was found to decrease the reactivity for the neutralsmore » CO, SO{sub 2}, CH{sub 4} and N{sub 2}O. For reactions of O{sup {minus}}(H{sub 2}O){sub n} with O{sub 2} and CO{sub 2}, no reaction was observed for n = 0, but hydration of O{sup {minus}} enabled reaction to proceed for O{sup {minus}}(H{sub 2}O){sub 1,2}. For reaction with NO, addition of one H{sub 2}O ligand to O{sup {minus}} increased the reactivity, while addition of a second H{sub 2}O caused a decrease in the rate constant to a value below that of the unsolvated O{sup {minus}}. No reaction was observed for any of the ions O{sup {minus}}(H{sub 2}O){sub 0-2} with H{sub 2}O. Temperature dependences of the rate constants were found to vary depending on the system.« less

SVL fluorescence spectroscopy was used to study V-T,R processes in collisions of 0/sup 0/ aniline with Ar, Xe, CO, CO/sub 2/, OCS, N/sub 2/O, acetylene, and allene. Populations were monitored in eight aniline vibronic levels. To first order, the experimental propensity rules for single-collision up pumping of 0/sup 0/ aniline to these levels are identical for all collision gases. An exception is the unusually large rate constant for population of the 1/sup 1/ level in collisions with allene, whose 11/sub 1/ level is nearly degenerate with the I/sup 1/ level in aniline; this may be evidence of an important V--Vmore » process. The endoergic up-pumping probabilities correlate well with ..mu../sup 1//sup ///sup 2/ for rare gas partners, but poorly for the other collision gases. No evidence is found that V-R processes contribute substantially to the rate constants for aniline in collision with CO or the polyatomic gases. The quantitative propensity rules provide a basis for a mode-to-mode collisional energy transfer theory, developed by Freed, in which the observed large V-T,R cross sections arise as a direct consequence of the intramolecular intermode coupling within large molecules such as aniline.« less

The electron-transfer reaction between O/sub 2/ and O/sub 2//sup -/ in hydrated gas-phase cluster has been studied with the ab initio MO method. The electronic part of the electron-transfer matrix element depends mainly on the conformation of the solute O/sub 2/O/sub 2//sup -/ transition state and is not much influenced by the solvent water molecules. On the other hand, the barrier height of the reaction increases with the number of the hydrating water molecules and controls a gradual decrease of the electron-transfer rate upon hydration.